VOC-free inkjet patterning method for the fabrication of "paperfluidic" sensing devices

A direct inkjet patterning method for paperfluidic devices using a hydrophobic UV-curable composition has been developed. Patterns are printed on the surface of untreated filter paper. After UV-curing, hydrophobic barriers are formed. To prevent liquid from leaching through the bottom of the device, a uniform layer of the same ink is printed on the backside of the paper, followed by UV-curing. Patterns are stable against surfactants and retain functionality for at least one month when stored at room temperature. The suitability for paperfluidic sensing is demonstrated on the example of a pH sensor.